Abstract

Summary In 1996 and 2006, recruits of theSwiss army participated in a dental survey.Similarly in 1995/96 and 2004/05, randomlyselected schoolchildren from 16 rural communitiesof the Canton of Zurich participatedin a dental survey. As part of these surveys,color slides were taken of the incisor teeth ofall recruits, as well as of third and fourth gradeschoolchildren. The slides (N = 2049) wereexamined for the presence of fluoride-associatedenamel opacities (FOP), using the Thylstrup-Fejerskov (TF) index. Two examiners (Aand B) assessed all slides. The examiners wereblind as to the year of survey. Examiner A recordedprevalences of FOP between 18% and27% depending on population; examiner Brecorded prevalences between 7% and 12%.The examiners’ influence on the estimation ofthe prevalence was obvious. The prevalencesreported should, therefore, be considered asrough estimates. FOP of TF score 2 were onlyobserved in approximately 1% of the participants.One examiner recorded a TF score 3 ina single individual. FOP therefore are not acosmetic problem and certainly not a publichealth concern.The prevalence of FOP decreased slightlyduring observation period I (recruits born1975–77 vs 1985–87) and period II (schoolchildrenborn 1985–87 vs 1994–96). However,the decline was statistically supportedin only one instance (Period I, Examiner B).